Answer:
The answer is A because the equation is  KEi+PEi=KEf+PEf
i means initial (before) and f means final (after)
 
        
             
        
        
        
Answer:
g / 16 
Explanation:
T = 2π 
 angular frequency ω = 2π /T
= 
ω₁ /ω₂ = 
Putting the values 
ω₁ = ω ,     ω₂ = ω / 4
ω₁ /ω₂ = 4 
4 =  
g₂ = g / 16
option d is correct. 
 
        
             
        
        
        
Answer:
E = 1.04*10⁻¹ N/C
Explanation:
Assuming no other forces acting on the proton than the electric field, as this is uniform, we can calculate the acceleration of the proton, with the following kinematic equation:

As the proton is coming at rest after travelling 0.200 m to the right,  vf = 0, and x = 0.200 m.
Replacing this values in the equation above, we can solve for a, as follows:

According to Newton´s 2nd Law, and applying the definition of an electric field, we can say the following:
F = mp*a = q*E
For a proton, we have the following values:
mp = 1.67*10⁻²⁷ kg 
q = e = 1.6*10⁻¹⁹ C
So, we can solve for E (in magnitude) , as follows:
 
⇒ E = 1.04*10⁻¹ N/C